CVSS 3.1
7.4 highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:HCVE-2026-4371
High (7.4) in mozilla thunderbird. EPSS 0.4% chance of exploitation in the next 30 days.
A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.
Severity
- EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-126, CWE-130
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mozilla:thunderbird